Fighting Fire with Firearms
—Globe-Democrat photo bp Paul Hodges
St. Louis, Mo., gas “scrubber” poses difficult extinguishing problem. Police marksmen lend a helping hand
SHOOTING HOLES in a tank to assist in controlling a fire involving the cylinder has occurred more in early 20th Century fire service fiction than in practice, and the technique is generally frowned on in most fire circles. A recent St. Louis, Mo., fire in a manufactured gas plant “scrubber” or filter tank created a hazardous problem which was finally solved by the use of this unorthodox method.
On September 4, workmen were in the process of dismantling the tall tank employing cutting torches. It is believed hot slag or heat conduction from the metal walls set fire to wooden rods, called hurdles, which were located at 2-foot intervals in the entire tank. The job foreman attempted to fight the ensuing blaze without assistance. After spending some time in a futile attempt to extinguish the flames, he finally decided to call the fire department. The first alarm was reported as an “open rubbish fire” at 4:01 p.m.
The scrubber or filter tank of the Laclede Gas Company at 151 Rutger Street was 93 feet high overall and measured 15 feet in diameter. It was bolted to an octagonal concrete base 18 inches high and securely anchored to the ground in depth.
The shell of the tank was steel throughout. The base sections were 1 inch thick to the top with a 6-inch lap above rivets. The tank had no vents at the top and the pressure relief at the base was a leveling device to emit oil in the event of excessive operational pressure. Due to the dismantling, this was inoperative. The tank was equipped with a number of pipes of various sizes for pumping oil into the tank and removing treated and untreated gas to an adjacent holder. There was a steel ladder on the outside of the tank and a catwalk atop the tank. Approximately 50 feet above the base at intervals, 1 3/4-inch pipe, flanged both sides, was bolted to the tank for steam cleaning. At several widely separated points, there were oval shaped inserts or recesses, apparently for cleanouts although their purpose could not be definitely ascertained. The cover on top of the tank was tightly secured by 22 bolted nuts. Six pipe openings had been made in one side of the cover for the injection of oil under pressure and its subsequent atomization. The couplings to these pipes had been removed.
There were many wooden hurdles inside the tank. Small wooden blocks, 3/4 inch thick and 2 inches square with a hole in the center were inserted on these wooden rods and served as separators for vanes 3/8 inch thick, approximately 6 inches long and 4 inches wide. The hurdles were placed at 2foot intervals at such angles that gas could not follow a direct path, but was forced to circulate through the grid, or pattern thus formed, as a part of the scrubbing process. Globules of the atomized oil would cling to hurdles and as gas passed through the maze, certain impurities were removed and recovered as useful by-products.
The installation was known as Station A and placed in operation in 1890. The filtering tank was added during World War I, to aid in the processing of the gas as well as to collect coal tar by-products, one of which was benzol used in the manufacture of certain explosives.
During the time before the arrival of the first company, the heat inside the unvented tank grew in intensity and the problem became more acute upon arrival. Ladder men were ordered to the top of the tank to ventilate. They were stymied due to the difficulty of removing the cover, the cramped space, as well as the heat and gases at top of tank. Weighing the factor of safety and time necessary to remove the cover and the growing intensity of the fire, all men were ordered to the ground.
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ST. LOUIS FIRE
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By this time the outer coating of paint on the tank was starting to blister, flake and fall to the ground. In
order to apply water into the tank to prevent a possible explosion or fissures and probable collapse, a port was ordered cut by torch at a point approximately 30 feet from the base. Smoke and flame emitted from this opening and the use of hose streams dirough this port did not alleviate the intensity of the fire to any great degree. Hose streams were played on the exterior of the tank to aid in reducing the pressure build-up, as well as providing cover for the exposures. In the immediate vicinity was a huge gasholder of the floating bell type and various plant buildings of an advanced age. The latter had wooden roof construction heavily coated with oil.
As the fire progressed in the tank, the sound of heat blast as well as eruptions due to the formation of gas pockets in the gridding were plainly audible and visible by the rocking of the tank on its base. By this time it was apparent that drastic action was necessary if the pressure within the tank was to be relieved and the possibility of an explosion with its subsequent hazard of burning wooden embers scattered far and wide was to be reduced.
It was then decided to summon firearm sharpshooters from the police department. Upon arrival, these men were requested to open holes in the plating at the highest point possible on the tank. Even though the danger of ricocheting was great on the rounded surface, 65 rounds of .30-calibre ammunition were fired expertly and accurately, opening a series of holes 2 or 3 inches in diameter approximately 6 to 12 inches below the top of the tank. Plumes of gas followed by smoke emitted as a result of the improvised but effective ventilation and most of the eruptions ceased.
Cellar pipes employed
With the danger of explosion somewhat alleviated, the firemen then began more positive methods of extinguishment. Cellar pipes and bent pipes were employed at the base and upper ports which aided in the cooling. These nozzles were somewhat impeded in their distribution and reach by parts of wooden hurdles that had begun to fall from the upper reaches of the tank, but officers and men held on doggedly in spite of the continued personal risk. Pipes on the exterior of the tank previously described were utilized where possible, and hose fittings were procured from the repair shop and sweated to piping that opened into the tank providing an improvised standpipe for flooding the tank with water.
The battle lasted through the night and into the following morning, before it appeared that the upper hand was being gained. With the final extinguishment not yet accomplished, it was decided even though smoke was still visible but not under excessive pressure, it was feasible to remove the cover from the tank top. Four members of the rescue squad were selected and with the necessary tools and equipment, plus life line and belt, ascended to the top of the tank covered by a heavy water spray from lines manned by engine crews on the adjacent gas holders. The terrain and cramped quarters did not lend itself to the use of aerial ladders at any time during the operations. These men succeeded in safely removing the tank cover and by lowering hose lines to various levels, extinguished the fire. Following a post mortem of this fire, it is believed that workmen dismantling similar tanks should remove bolted or heavy covers at the top as a preliminary safety precaution prior to burning or use of cutting torches. The lack of top openings for pressure relief as well as extinguishment was the foremost problem at this particular fire. There still remain several of these tanks on gas manufacturing property in St. Louis. This type of installation has obviously become obsolete and may pose similar problems in the future.